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Serotonin Receptor Antagonists

Posted by medliorator on September 11, 2009


All 5-HT3 antagonists are identified by the suffix -setron

The following are  5-HT3  antagonists serum half- lives:

  • Dolasetron (Anzemet): 7-9 hours.
  • Granisetron (Kytril, generic) 9-11 hours.
  • Ondansetron (Zofran, generic): 3.9 hours.
  • Palonosetron (Aloxi): 40 hours.

At equivalent doses for the prevention of acute emesis, 5-HT3 serotonin receptor antagonists have equivalent safety and efficacy and can be used interchangeably… their clinical use is limited to situations that produce vagal stimulation (eg. surgery) and chemotherapy

5-HT activates 5-HT3 receptors on extrinsic intestinal vagal and spinal afferent nerves. These afferent fibers have projections to the  nucleus tractus solitarius (NTS) and the area postrema (AP).

5HT3 antagonists are superior to metoclopramide, droperidol, and dimenhydrinate in the pharmacologic prophylaxis of postoperative nausea and vomiting. Recently, the FDA added a boxed warning to metoclopramide because of an increased risk of tardive dyskinesia

According to experimental data, these agents have shown to induce minor electrocardiographic changes. It is recommended not to administer dolasetron to patients with prolonged QT or with drugs that may prolong the QT interval.

Serotonin 5-HT3-receptor antagonists: pharmacokinetics, MOA, indications and adverse effects [Pharmamotion]

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